Department of Anatomy and Cell Biology, Martin Luther University Faculty of Medicine, Grosse Steinstrasse 52, 06097 Halle (Saale), Germany.
Ann Anat. 2009 Nov;191(5):485-95. doi: 10.1016/j.aanat.2009.06.002. Epub 2009 Jun 26.
During preimplantation development, embryos of many species are known to express up to five isoforms of the facilitative glucose transporter proteins (GLUT). Development of hamster blastocysts is inhibited by glucose. We therefore investigated GLUT isoform and insulin receptor (IR) expression in hamster preimplantation embryos cultured in glucose-free medium from the 8-cell stage onwards. We show that GLUT1, 3 and 8 mRNA are constitutively expressed from the 8-cell to the blastocyst stage. The IR is expressed from the morula stage onwards. Messenger RNA of the insulin-responsive GLUT4 was not detected at any stage. GLUT1 and 3 were localised by immunocytochemistry. GLUT1 was expressed in both embryoblast and trophoblast, in the latter, mainly in basal and lateral membranes directed towards the blastocoel and embryoblast. GLUT3 was exclusively localised in the apical membrane of trophoblast cells. We show that hamster preimplantation embryos express several GLUT isoforms thus closely resembling embryos of other mammalian species. Despite endogenous IR expression, the insulin-sensitive isoform GLUT4 was not expressed, indicating that the insulin-mediated glucose uptake known from classical insulin target cells may not be relevant for hamster blastocysts.
在植入前胚胎发育过程中，已知许多物种的胚胎表达多达五种易化葡萄糖转运蛋白（GLUT）同工型。仓鼠囊胚的发育受到葡萄糖的抑制。因此，我们研究了从 8 细胞阶段开始在无葡萄糖培养基中培养的仓鼠植入前胚胎中的 GLUT 同工型和胰岛素受体（IR）表达。我们表明，GLUT1、3 和 8 mRNA 从 8 细胞阶段到囊胚阶段持续表达。IR 从桑葚胚阶段开始表达。在任何阶段都未检测到对胰岛素有反应的 GLUT4 的信使 RNA。通过免疫细胞化学定位 GLUT1 和 3。GLUT1 在胚胎细胞和滋养层中表达，在后者中，主要在朝向囊胚腔和胚胎细胞的基底和侧膜中表达。GLUT3 仅定位于滋养层细胞的顶膜。我们表明，仓鼠植入前胚胎表达几种 GLUT 同工型，因此与其他哺乳动物胚胎非常相似。尽管存在内源性 IR 表达，但不表达胰岛素敏感的 GLUT4 同工型，表明经典胰岛素靶细胞中已知的胰岛素介导的葡萄糖摄取可能与仓鼠囊胚无关。
